The need for the invention has arisen from meat processors being required to provide leaner cuts of meat to their customers and/or meat cuts with specific trim requirements. Quite often the products they produced must be hand trimmed to meet the customer lean specification. This is both labor intensive and results in the loss of valuable lean or desired product.
For example, with pork butts (shoulders), it is common to require that several square inches of the Trapezius muscle be exposed to meet customer trim requirements. For pork hams, it is common practice to specify trim requirements for the amount of muscle tissue exposed and/or the amount of fat or membrane left on the muscle. Pork loins have similar requirements for the amount of muscle exposure required to meet product specifications.
The current methods used to determine muscle location for trimming purposes are guessing where the trimming should take place and trimming several layers of materials covering the muscle to be exposed until the proper trim has been achieved. On the one hand, guessing results in poor yields due to inaccurately locating the muscle or surface to be trimmed/separated. On other hand, removing covering materials several layers at a time is time consuming, ergonomically detrimental to the trimmer, and also results in yield losses.
It is also not common to identify lean for trimming purposes using a non-invasive method. Probes that use electronic eyes to discern the difference between fat and lean have been used to adjust for fat thickness relative to a lean layer. These probes take a reading of the layers to identify the fat or lean by the amount of light each reflects. They do not identify a specific muscle or substance as a reference point for trimming. A distinct disadvantage of these probes is that they puncture the product to be trimmed and cause damage to the product. Ultrasound transducers eliminate this unwanted result.
Use of Ultrasound is common in the meat industry. It is widely used as a means for grading carcasses to determine their value based on fat and lean content. It is also used to determine a fat to lean ratio or the depth of a muscle or the thickness of fat, again for grading purposes. The use of Ultrasound for the purpose of removing a layer of fat from meat, particularly pork bellies, to achieve a preferred thickness of the belly is old. The use of Ultrasound to predict leanness, lean to fat, and thickness of a piece of meat is common place. U.S. Pat. No. 4,947,517 uses Ultrasound to facilitate trimming, but fails to reference pre-established trim requirements.
It is therefore a principal object of this invention to use Ultrasound to identify natural conditions in the meat portion; evaluate these conditions electronically, and control the trimming of the meat portion in accordance with predetermined trimming standards and requirements used in the evaluation.
These and other objects will be apparent to those skilled in the art.